Pacquiao's next bout is set for Nov. 23 in Macau, China, against former world lightweight champion Brandon Rios.
Promoter Bob Arum brought up the tax issue when talking to the Los Angeles Times Friday.
"By fighting outside the country, as he's doing in this Rios fight, Manny doesn't have to pay U.S. taxes anymore -- at a rate of 40 percent for a foreign athlete," Arum said.
"If this pay-per-view and other things take off like we think they may, I can't imagine Pacquiao will ever again fight in the U.S."
Arum said the pay-per-view fight in China could bring in $10 to $20 million.
"It changes everything. Will it work? We'll see in November," he said.
Boxing fans have been itching for a match between Pacquiao and Floyd Mayweather Jr., who is taking on unbeaten world super-welterweight champion Saul "Canelo" Alvarez Sept. 14 in Las Vegas.